The invention relates to a radio communication network based on digital local exchanges which contain digital subscriber line units with digital subscriber line modules to which subscriber lines with network terminating units at the subscriber end are connected, each network terminating unit being connected to a subscriber line module via the subscriber line by means of a data channel and the data channels being concentrated to one or more composite data channels in the local exchange, the composite data channels being connected via a data network to a data processing system of a service provider.
Such communication systems are used for setting up "Intelligent Networks", or the mobile telephone C network. Intelligent networks also form the basis for setting up future cellular radio networks. They make it possible to tie service providers into the conventional telephone network. Concepts are described, for example, in telcom report, 1989, volume 4 (page 102-105) and volume 5 (page 142-145) under the titles "Intelligente Netzeleistungsfahige Basis fur zukunftige Dienste" (Intelligent Networks-Efficient Basis for Future Services) and "Intelligente Netze beschleunigen Einfuhrung neuer Dienste" (Intelligent Networks Accelerate the Introduction of New Services).
ISDN exchanges are also described in, inter alia, telcom report, March/April 1986, volume 2, page 111-117 under the title "Digitale Teilnehmerleitungseinheitim System EWSD fur ISDN-Teilnehmeranschlusse" (Digital subscriber line unit in the EWSD system for ISDN subscriber lines). Two voice channels and one data channel are switched through via a switching network as a connection between two subscribers. The data channel is operated as a packet-oriented channel for the subscriber signalling and for slow data (packetized data including telemetry data). The different data are separated in the digital subscriber line module within a digital subscriber line unit. The packet data are conducted via a p channel to an interface module and the data of the subscriber signalling are conducted via an s channel to a second interface module. The exchange can also be connected to, inter alia, data networks, for example a packet data network. Such a communication system enables the network operator to offer various voice and data services to the subscribers.
From WO 86/6915, a system is known by means of which a radio network for cordless telephones is operated by interposition of a separate radio exchange in the area of a private branch exchange. Voice transmission is digital. In this arrangement, connections with several mobile sections can be set up for each base station. If necessary, the radio exchange can switch a connection from one base station to another one which has a better transmission quality. Switching information items are exchanged via a common signalling channel or a time slot in the voice channel. This is therefore a private radio telephone network of the mobile telephone network type. The user circle is restricted to the few mobile sections connected and there is no separate authorization check. Subscriber identification will therefore generally occur via the access number and a personal identification number of the mobile section. Voice transmission is digital.